Catalyst obtained by prepolymerization of polyolefin and olefin polymerization method using the same

ABSTRACT

The present invention provides a prepolymerized olefin polymerization catalyst and olefin polymerization method using the same. More particularly, the present invention provides a prepolymerized catalyst that is encapsulated with macromonomers produced by polymerizing olefin monomers with a vinyl-terminated polysiloxane compound in the presence of a solid titanium catalyst for olefin polymerization having been previously surface treated with silane compounds containing two or more vinyl groups, and a method for producing polyolefin having a high melt strength using the catalyst.

TECHNICAL FIELD

[0001] The present invention relates to a prepolymerized catalystobtained by prepolymerization of polyolefin and an olefin polymerizationmethod using the same. More specifically, the present invention relatesto a prepolymerized olefin polymerization catalyst prepared in such away that macromononers of high molecular weight are encapsulated aroundthe catalyst optimized for olefin polymerization, and to a method forpolymerization of polyolefin with high melt strength by using theprepolymerized catalyst.

BACKGROUND ART

[0002] Conventional polypropylenes with linear structure are notsuitable for the process which is conducted in a melt state (forexample, foaming, heat molding, extrusion coating) because of its lowmelt strength in comparison with polyethylene. However, when a longchain branch is introduced to the polymer, it shows high melt strengthas it shows easy flow properties by reducing attraction forces betweenmacromolecular chains during the processing and it functions asincreasing the melt strength by crosslinking between neighboring longchains during molding process (especially, in a use requiring valuestabilities such as a large scale blow). As a method for producing highmelt strength polyolefins by introducing these long chain branches, amethod comprising following steps was generally used: forming radicalsof polyolefins coming out of the polymerization reaction vessels throughelectronic radiation or reaction extrusion method, reacting theseradicals and thereby forming long chain branches in a chain typepolyolefins. Therefore, if a polymerization method capable of directlypolymerizing polyolefins useful as molding material and with high meltstrength during polymerization steps could be developed, it is expectedthat the use of polyolefin as molding materials would be expanded.

DISCLOSURE OF INVENTION

[0003] In order to produce polyolefin with high melt strength atpolymerization stage, the object of the present invention is to provideprepolymerized olefin polymerization catalyst and the method forpolymerizing olefin by using the catalyst. The olefin prepolymerizedcatalyst of the present invention have funtionalized active site whichcan introduce long chain branch to the polymer and includemacromolecular monomer, and by using this catalyst in polymerizingolefin and introducing long branch into the polymer duringpolymerization, polyolefin with high melt strength can be produced.

[0004] The present invention relates to a catalyst encapsulated withmacromoners around it (hereinafter referred to as ‘prepolymerizedcatalyst’) and which is capable of forming branches to the olefinpolymers, wherein said catalyst is prepared by prepolymerization ofsolid titanium catalyst for olefin polymerization with olefinmacromoner/mutifuntional compounds, and also relates to a method forhigh melt strength polyolefin polymerization by using the prepolymerizedcatalyst.

[0005] The term “polymerization” herein has the meaning includingpreparation of copolymerization of an olefin with other α-olefins aswell as preparation of monopolymer of olefin.

[0006] The prepolymerized catalyst of the present invention is preparedby surface treating solid titanium catalyst for olefin polymerizationwith silane compounds having vinyl group of two or more of double bonds,and then conducting prepolymerization reactions by mixing the surfacetreated catalyst and mixture of olefin monomer and vinyl terminatedpolysiloxane with double bond at the terminal group, therebyencapsulating the catalyst by polymerizing the macromonomer around thecatalyst. Compared to the solid titanium catalyst, the prepolymerizedcatalyst according to the present invention has good catalystactivities, and is capable of polymerizing a polymer having broadmolecular weight distribution and high solid regularity and also capableof forming long chain branches to the polyolefins.

[0007] As the solid titanium catalysts used in the preparation of theprepolymerized catalyst of the present invention, any of theconventional solid titanium catalyst for polyolefin polymerization maybe used, and it may be prepared by various methods. For example, it maybe prepared by directly contacting the magnesium compounds free ofreducibility with the titanium compound in a liquid state in thepresence of electron donors not having active hydrogen, i.e, directlycontacting each said reactants in the liquid state, or it may beprepared by forming solid catalyst with magnesium compounds and titaniumcatalyst in the absence of electron donors having no active hydrogen andthen reacting by contacting the catalyst thus obtained with electrondonors.

[0008] Among the preparation methods of solid titanium catalyst used inthe preparation of the prepolymerized catalyst of present invention, themost common methods are, for example, comprise the following steps ofcontacting the magnesium compounds with the titanium compounds having atleast one or more halogen atoms, and if necessary, treating the productsthus obtained with electron donors. Some of above methods are describedin German Patent Laid open Nos. 2,230,672, 2,504,036, 2,553,104 and2,605,922, and Japanese Patent Laid open Nos. 51-28189; 51-136625 and52-87486. Further, a method for preparing solid titanium compoundscontaining electron donors from titanium compounds in a liquid statewhich is derived from liquid state magnesium is described in JapanesePatent Laid open No. 79-40293.

[0009] Also, as solid titanium catalyst used in the preparation of theprepolymerized catalyst of present invention, the conventionalZiegler-Natta catalyst, which is described in U.S Pat. Nos. 4,482,687;4,277,372; 3,642,746; 3,642,772; 4,158,642; 4,148,756; 4,477,639;4,518,706; 4,946,816; 4,866,022; 5,013,702; 5,124,297; 4,330,649;European Patent No. 131,832; Japanese Patent Laid open Shou 63-54004etc., may be used.

[0010] One preferable example among the methods for preparing the solidtitanium catalyst is as follows, and in the examples of the presentinvention, magnesium supported solid complex titanium catalyst wasprepared by these methods and then used, i.e.,

[0011] (i) preparing magnesium compounds solution by dissolvingmagnesium compounds having no reducibility into electron donors,

[0012] (ii) reacting thus magnesium solution with transition metalcompounds, silicone compounds, tin compounds or a mixture thereof andthereby precipitating solid particles,

[0013] (iii) then, reacting the precipitated solid particles withtitanium compounds and electron donors, then washing with hydrocarbonand thereby preparing solid catalyst articles having controlled particletypes.

[0014] The magnesium compounds having no reducibility used in thepreparation of solid titanium catalyst as above includes magnesiumhalides such as magnesium chloride, magnesium bromide, magnesium iodideand magnesium fluoride, alkoxy magnesium halides such as methoxymagnesium chloride, ethoxy magnesium chloride, isopropoxy magnesiumchloride, butoxy magnesium chloride and octoxy magnesium chloride,aryloxy magnesium halides such as phenoxy magnesium chloride andmethylphenoxy magnesium chloride, alkoxy magnesium such as ethoxymagnesium, isopropoxy magnesium, butoxy magnesium and octoxy magnesium,aryloxy magnesium such as phenoxy magnesium and dimethyl magnesium andmagnesium salts of carboxylic acid such as lauryl magnesium and stearicacid magnesium.

[0015] These magnesium compounds can be used in the form of complexcompound of other metals or with a mixture of other metals, or a mixtureof two or more magnesium compounds. Preferably, these magnesiumcompounds are magnesium compounds containing hydrogen, magnesiumchloride, alkoxy magnesium chloride, preferably alkoxy magnesiumchloride having C₁˜C₁₄ alkoxy groups and aryloxy magnesium chloride,preferably aryloxy magnesium chloride having C₅˜C₂₀ aryloxy groups.

[0016] Generally, the above mentioned compounds can be represented as asimple chemical formula, but sometimes there is a case it can not berepresented as such according to the method for their preparation. Suchcompounds are generally considered to be a mixture of above mentionedcompounds. For example, compounds obtained by a method which is reactingmagnesium compounds with alcohols or phenols in the presence ofhalosilane, phosphate pentachloride or thionly chloride and by pyrolysisof Grignard reagent or a degradation method using hydroxyl groups,carbonyl ester bond, ether bond or similar kind of compounds are whatthey are considered to be a mixture of various compounds depending onthe reagents or degree of reaction. And these compounds also can be usedin the present invention.

[0017] The magnesium compounds are reacted with one or more electrondonors which are selected from the groups consisting of alcohols,organic carboxylic acids, aldehydes, amines and a mixture thereof, andthereby producing a solution of magnesium compounds. A solution ofmagnesium compounds can be produced by mixing hydrocarbon solvent withelectron donors and then heating them. Examples of hydrocarbon solventused for these object include aliphatic hydrocarbons such as pentane,hexane, heptane, octane, decane, dodecane and kerosene, cyclichydrocarbones such as cyclopentane, methycyclopentane, cyclohexane andmethylcyclohexane, aromatic hydrocarbons such as benzene, toluene,xylene, ethylbenzene, cumene and simene and halo hydrocarbons such asdichloroethane, dichloropropane, dichloroethylene, trichloroetylene,tetrachlorocarbon and chlorobenzene.

[0018] In the step (i) of prapraring a solution of magnesium compounds,when alcohol is used as an electron donor to dissolve magnesiumcompounds having hydrogen in hydrocarbon solvents, the suitable alcohols/magnesium compounds molar ratio is at least 0.5 mol, preferably about1.0 to 20 mol, more preferably about 2.0 to 10 mol.

[0019] When aliphatic hydrocarbons or cyclic hydrocarbons are used ashydrocarbon solvents, alcohols are used as above mentioned amounts,however, if alcohols having 6 or more carbon atoms among these alcoholsare used and the alcohols/magnesium compounds molar ratio is at least0.5, preferably 1 or more, the magnesium compounds having halogen can bedissolved and catalyst components having high performaces can beobtained by using small amount of alcohols. And if alcohols having 5 orless carbon atoms are used, the total amount of alcohols should be atleast about 15 moles per magnesium compounds having halogen, and thecatalyst components thus obtained has catalytic activities less thanthose obtained by using alcohols of previously mentioned method. On theother hand, when aromatic hydrocarbons are used as hydrocarbon solvents,magnesium compound having hydrogen can be dissolved by using about 20moles, preferably about 1.5 to 12 moles per magnesium compounds havinghydrogen irrespective of the types of alcohols.

[0020] The reaction of contacting magnesium compounds with electrondonor alcohols is conducted in the medium of hydrocarbons. Thesecontacting reactions are carried out at room temperature or hightemperature, for example, about 30° C. to 200° C., preferably about 60°C. to 150° C. for about 15 minutes to about 5 hours, preferably about 30minutes to about 3 hours.

[0021] Examples of alcohols used as electron donor in the step (i)include aliphatic alcohols having at least 6 carbon atoms, preferably 6to 20 carbon atoms such as 2-methylpentanol, 2-ethylbutanol, n-heptanol,n-octanol, 2-ethylhexanol, decanol, dodecanol, tetradecyl alcohol,undecenol, oleyl alcohol and stearyl alcohol, cyclic alcohols such ascyclohexanol and methylcyclohexanol and aromatic alcohols such as benzylalcohol, methylbenzyl alcohol, isopropylenebenzyl alcohol,α-methylbenzyl alcohol and α, α-dimethylbenzyl alcohol. Examples ofalcohols having 5 or less carbon atoms include methanol, ethanol,propanol, butanol, ethyleneglycol and methylcarbitol.

[0022] The solutions of magnesium compounds thus obtained are reactedwith transition metal compounds such as titanium compounds, siliconcompounds, tin compounds or mixtures thereof and then crystallizes intoa globular solid material (step (ii)). At this time, the amount of thetransition metal etc used may be suitably changed. For example, thesuitable amount of transition metal compounds, silicon compounds, tincompounds or mixtures thereof per 1 mole of magnesium compounds is inthe range of 0.1 mol to 20 mol, preferably 0.1 mol to 10 mol, morepreferably 0.2 mol to 2 mol.

[0023] In the step (ii), when the magnesium compounds in the liquidstate are crystallized, the shape and size of the magnesium carrierchanges according to the reaction conditions, and preferably, thetemperature of contacting reaction is in the range of about −70° C. to200° C. However, it is preferable that this reaction is conducted in therange of about 20° C. to 150° C. because it is generally preferable toavoid high temperature during the mixing process to obtain particulateor globular type precipitate or the precipitate of solid products doesnot occur if the contacting temperature is too high.

[0024] Solid complex titanium catalyst is produced by reacting magnesiumcompounds in the solid particulate state thus obtained with titaniumcompounds and electron donors (step (iii)). Examples of electron donorsused in this step include generally electron donors having oxygen atomsuch as water, alcohols, phenols, ketones, aldehydes, carboxylic acids,esters and acid amides, electron donors having nitrogen atom such asammonia, amines, nitriles and isocyanic acid salts, more particularlyalcohols having 1 to 18 carbon atoms such as methanol, ethanol,propanol, pentanol, hexanol, octanol, dodecanol, octadecyl alcohol,benzyl alcohol, phenlyethyl alcohol, cumyl alcohol and isopropylbenzylalcohol, ketones having 6 to 15 carbon atoms which is capable of havinglower phenyl groups such as phenol, cresol, xylene, ethylphenol,propylphenol, cumylphenyl and naphthol, aldehydes having 2 to 15 carbonatoms such as acetaldehyde, propionylaldehyde, octylaldehyde,benzaldehyde, tolueyl aldehyde and nathphaldehyde, organic acid estershaving 2 to 18 carbon atoms such as methylformate, methylacetate,vinylacetate, propylacetate, octylacetate, cyclohexylacetate,ethylpropionate, methylbutyrate, ethylvalerate, methylchloroacetate,ethyldichloroacetate, methylmetacrylate, ethylcrotonate,ethylcyclohexylcarboxylate, phenylsalicylate, methyltoluate,ethyltoluate, amyltoluate, ethylethylsalicylate, methylanistate,ethylanistate, ethylethoxysalicylate, γ-buyrolactone, δ-butyrolactone,coumarine, phthalate, cyclohexylacetate, methylvalerate, etyhlcitrate,phenylbenzoate, propylbenzoate, butylbenzoate, cyclohexylbenzoate andethylene carbonate, acid halides having 2 to 15 carbon atoms such asacetylchoride, benzylchoride, tolueylchloride and anisylchloride, etherssuch as methylether, ethylether, isopropylether, butylether, amylether,tetrahydrofuran, anisole and diphenylether, amines such as methylamine,ethylamine, diethylamine, tributylamine, piperidine, tribenzylamine,aniline, pyridine, pynoline and tetramethylethylenediamine, nitrilessuch as acetonitrile, benzonitrile and tolunitrile and compounds ofaluminum, silicon and tin etc having above mentioned functional groupswithin the molecules. Also, ester derivatives ofmonoethyleneglycol(MEG), diethyleneglycol(DEG), triethyleneglycol(TEG),polyethyleneglycol(PEG), monopropyleneglycol(MPG) anddipropyleneglycol(DPG) such as of acetate, propionate, n- andiso-butyrate, benzoate, toluate etc can preferably be used. Examples ofthese benzoate ester derivatives include monoethyleneglycolmonobenzoatemonoethyleneglycoldibenzoate, diethyleneglycolmonobenzoate,diethyleneglycoldibenzoate, triethyleneglycolmonobenzoate,triethyleneglycoldibenzoate, monopropyleneglycolmonobenzoate,dipropyleneglycolmonobenzoate, dipropyleneglycoldibenzoate,tripropyleneglycolmonobenzoate etc. These electron donors can be used asa mixture of 2 or more thereof, preferably, esters of aromatic compoundsare suitable. However, these electron donors are not always needed asstarting materials and they can be used as adducts of other compounds orcomplex compounds. The amount of these electron donors can becorrespondingly changed, and it can be used, preferably, in the range ofabout 0.001 mol to about 10 mol, more preferably, 0.01 mol to 5 mol,most preferably, 0.05 to about 1, per mole of the magnesium compounds.

[0025] Examples of the titanium compounds in the liquid state to bereacted with the magnesium compounds in the solid particulate state inthe step (iii) are preferably tetravalent titanium compounds of theformula Ti(OR)mX₄-m (wherein R represents hydrocarbon group having 1 to10 carbon atoms, X represents a halogen atom and m is a numberrepresented by 0≦m≦4). Examples of these titanium compounds are titaniumtetrahalides such as TiCl₄, TiBr₄ and TiI₄, titanium tihalides such asTi(OCH₃)Cl₃, Ti(OC₂H₅)Cl₃, Ti(OC₄H₉)Cl₃, Ti(OC₂H₅)Br₃ andTi(O(i-C₂H₅))Br₃, alkoxy titanium dihalides such as Ti(OCH₃)₂Cl₂,Ti(OC₂H₅)₂Cl₂, Ti(OC₄H₉)₂Cl₂ and Ti(OC₂H₅)₂Br₂, alkoxy titaniummonohalides such as Ti(OCH₃)₃Cl, Ti(OC₂H₅)₃Cl, Ti(OC₄H₉)₃Cl andTi(OC₂H₅)₃Br, tetraalkoxy titanium such as Ti(OCH₃)₄, Ti(OC₂H₅)₄,Ti(OC₄H₉)₄ and mixtures thereof. Among these the halogen-containingtitanium compounds, particularly titanium tetrahalides, moreparticularly titanium tetrachlorides are preferred.

[0026] These titanium compounds are used at least 1 mole, commonly 3moles to about 200 moles, preferably about 5 moles to 100 moles per moleof magnesium compounds. When contacting magnesium compounds withtitanium compounds in the liquid state, it is preferable that thereaction temperature is maintained at low temperature during mixing, andthen gradually increased. For example, contacting reaction of the twocompounds are conducted at −70° C. to about 50° C. so that the reactionis not proceed rapidly, and then the reaction temperature is graduallyincreased and maintained for a sufficient time at 50° C. to 150° C., andthen the products are washed with hydrocarbons used in thepolymerization reaction until the free titanium is not detected.According to these preparation method for catalyst, solid titaniumcatalyst with high performances can be prepared.

[0027] It is preferable that the solid titanium catalyst used in thepresent invention has more than about 4 of halogen/titanium molar ratio,and does not essentially liberate free titanium compounds by washingwith hexane at room temperature. Preferable examples of solid titaniumcatalyst are catalyst that the halogen/titanium molar ratio is about 4or more, more preferably about 5 or more, most preferably about 8 ormore, the magnesium/titanium molar ratio is in the range of about 3 ormore, more preferably about 5 to 50 and the electron donor/titaniummolar ratio is about 0.2 to about 6, more preferably about 0.4 to about3, further more preferably about 0.8 to about 2. Further, specific areaof the solid is 10 m²/g or more, more preferably 50 m²/g or more, mostpreferably 100 m²/g or more. It is preferable that the X-ray spectrum ofthe solid titanium catalyst represents amorphous properties irrespectiveof the starting magnesium compounds or more amorphous state than thecommon magnesium dihalides of the commercial grade.

[0028] To prepare the prepolymerized catalyst according to the presentinvention, firstly surface of the solid complex titanium catalyst asabove mentioned is treated with silane compounds having two or morevinyl groups. Examples of the divinyl type silane compounds used at thisstage are divinyl dimethyl silane, divinyl diphenyl silane, divinyldiethyl silane, divinyl diisobutyl silane, divinyl silane dihydride.These compounds are used in the amount of 2 mole to 200 moles per moleof magnesium compounds when they are used in the surface treatment. Whensilane compound of below 2 moles per 1 mole of magnesium compound isused, long chain cannot be effectively made due to the shortage of thesilane compound and the effect is not substantially improved. Whensilane compound of over 200 moles per 1 mole of magnesium compound isused, substantial reduction of catalyst activity makes it impossible touse the catalyst in the polymerization process. The reaction between thesolid titanium catalyst and these compounds for surface treatment isconducted by contacting these two compounds at −70° C. to 50° C. and atthis time, solvents may or may not be used.

[0029] To prepare the prepolymerized catalyst according to the presentinvention, prepolymerization reaction is carried out against the solidtitanium catalyst thus surface treated. The prepolymerization process isconducted by reacting olefin monomers with vinyl terminated polysiloxanewith double bond at the terminal group at the temperature or −50° C. to50° C. in the presence of above surface treated solid titanium catalyst,aluminum alkyl and electron donors, thereby polymerizing macromonomerson the surface of the catalyst through the simultaneous reaction ofcompounds having double bond and treated on the catalyst surface, olefinmonomers and vinyl terminated polysiloxane with double bond at theterminal group. The macromonomers are composed of olefins, silanecompounds having double bonds and vinyl terminated polysiloxane compoundwith double bond at the terminal group and encapsulates the catalystsurface. The composition of olefin, vinyl terminated polysiloxane withdouble bond at the terminal group and silane compounds in themacromonomers thus produced is composed of 1 to 99 weight percent ofolefins, 0.01 to 10 weight perecent vinyl terminated polysiloxane withdouble bond at the terminal group, and 0.001 to 1 weight percent ofsilane compounds. Among these, preferably the compounds are composed of70 to 95 weight percent of olefins, 0.1 to 5 weight perecent vinylterminated polysiloxane with double bond at the terminal group, 0.01 to1 weight percent of silane compounds. Examples of olefin monomers usedat this stage are one or more compounds selected from the groupconsisting of ethylene, propylene, 1-butene, 1-hexene and 1-octene, andvinyl terminated polysiloxane with double bond at the terminal group canhave structure as below.

H₂C═CH—SiR₂—O—(SiR₂—O)_(n)—SiR₂—CH═CH₂

[0030] (n=0˜100, R=alkyl, alkoxy, hydrogen or phenyl)

[0031] The macromonomers polymerized around the catalyst are reactedwith propylene monomers during the main polymerization reaction andthereby forms long chain branches or networks. The molecular weight ofthese macromonomers is preferably in the range of 500 to 100,000, andamong these, the compounds which is showing excellent polymerizationactivities in the main polymerization reaction are molecules havingmolecular weight in the range of 1000 to 10,000.

[0032] The prepolymerized catalyst thus produced according to thepresent invention is useful for polymerization of olefins such asethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-butene,vinylcycloalkane or cycloakane. Particularly, these catalysts are usefulfor polymerization of α-olefins having 3 or more carbon atoms,copolymerization between these compounds, copolymerization between thesecompounds having 20 mole percent or less of ethylene andcopolymerization between polyunsaturated compounds such as conjugated ornonconjugated dienes.

[0033] The method for olefin polymerization according to the presentinvention is comprising polymerizing or copolymerizing olefins in thepresence of catalyst system which is composed of component (a), (b) and(c):

[0034] (a) the prepolymerized catalyst produced by above mentionedmethod, i.e, macromonomer encapsulated-prepolymerized catalyst which isobtained by prepolymerizing olefin monomer and diene compounds withsolid titanium compounds which is essentially composed of magnesiumcompounds, titanium compounds, electron donors and silane compoundshaving 2 or more double bonds.

[0035] (b) Organometallic compounds of Group I or III metals of thePeriodic Table.

[0036] (c) external electron donors.

[0037] Examples of the organometallic compounds used as cocatalyst inthe polymerization method of the present invention are trialkylaluminumsuch as triethylaluminum and tributylaluminum, trialkenylaluminum suchas triisoprenylaluminum, partially alkoxylated alkylaluminum (forexample, dialkylaluminumalkoxide such as diethylaluminumethoxide anddibutylaluminumbutoxide, alkylaluminum sesquialkoxide such asethylaluminum sesquiethoxide and butylaluminum sesquiethoxide),alkylaluminum halides such as ethylaluminum dichloride, propylaluminumdichloride and butylaluminum dibromide, partially halogenated aluminum,aluminum hydride, dialuminum hydride such as diethylaluminum hydride anddiethylaluminum hydride and partially alkoxylated halogenatedalkylaluminum such as butylaluminum butoxychloride and ethylaluminumethoxybromide. Among these, trialkylaluminum is preferable.

[0038] External electron donors(c) used in the polymerization method ofthe present invention may be a external electron donor materials whichis conventionally used in the polymerization of olefins. Such a externalelectron donors are generally used to optimize the catalytic activitiesand stereoregularities in the olefin polymerization. Examples of theexternal electron donors which is useable in the present invention areorganic compounds containing oxygen, silicon, nitrogen, sulfur andphosphorus atoms such as organic acid, organic acid anhydride, organicacid ester, alcohol, ether, aldehyde, ketone, silane, amine, amineoxide, amide, diol, phosphate ester and mixtures thereof. Particularlypreferable external electron donors are organic silicon compounds havingalkoxy groups, i.e, alkoxy silane, and examples of these compoundsinclude aromatic silanes such as diphenyldimethoxy silane,phenyltrimethoxy silane, phenylethyldimethoxy silane andphenylmethyldimethoxy silane, aliphatic silanes such asisobutytrimethoxy silane, diisobutydimethoxy silane,diisopropyldimethoxy silane, di-t-butyldimethoxy silane,t-butyltrimethoxy silane, cyclohexylmethyldimethoxy silane,dicyclopentyldimethyldimethoxy silane, dicyclohexyldimethoxy silane,2-novonantriethoxy silane, 2-novonanmethyldimethoxy silane andvinyltriethoxy silane and mixtures thereof, among these compounds,particularly branched alkyl dialkoxy silane such as diisobutyl dimethoxysilane and cycloalkyl dialkoxy silane such as dicyclopentyl dimethoxysilane are effective. The above compounds can be used as a single or asmixtures thereof.

[0039] When the polymerization method of the present invention isapplied to liquid state polymerization, inactive solvents such ashexane, heptane or kerosene can be used as a reaction medium, and alsothe olefin itself can be used as reaction medium. In the case of liquidstate polymerization process, preferable concentration of theprepolymerized catalyst(a) in the polymerization reaction system isabout 0.001 to about 5 mmol, more preferably about 0.001 to about 0.5mmol, calculated in the basis of titanium atoms in the 1 liter ofsolvents. In the case of gaseous state polymerization, preferable amountof the prepolymerized catalyst(a) is about 0.001 to about 5 mmol, morepreferably about 0.001 to about 1.0 mmol, further preferably 0.01 toabout 0.5 mmol, calculated in the basis of titanium atoms in the 1 literof polymerization zone.

[0040] Also, the ratio of organometallic atoms in the component(b) isabout 1 to 2,000 mol, preferably about 5 to 500 mol per mole of titaniumatom in the catalyst(a) and the ratio of external electron donors(component(c)) is about 0.001 to 10 mol, preferably about 0.01 to 2 mol,more preferably about 0.05 to 1 mol per mole of organometallic atoms inthe component(b), calculated in the basis of nitrogen or silicon atoms.

[0041] The olefin polymerization or copolymerization in the presence ofthe catalyst system of the present invention is conducted as the sameway as in the olefin polymerization process using conventionalZiegler-type catalyst. Particularly, the polymerization orcopolymerization is essentially conducted in the absence of oxygen orwater. The polymerization reaction of olefins may be conducted,preferably at the temperature of about 20° C. to 200° C., morepreferably about 50° C. to 180° C. and under the pressure of atmosphericpressure to 100 atms, more preferably about 2 to 50 atms. Thesepolymerization can be conducted bacthwise, semibachwise or continously,or it can be conducted in the steps more than 2 having differentreaction conditions.

BEST MODE FOR CARRYING OUT THE INVENTION

[0042] The following examples and comparative examples illustrate thepresent invention more specifically, but the present invention is notlimited thereto.

EXAMPLE 1 Preparation of the Prepolymerized Catalyst(a)

[0043] Step 1: Preparation of Solution of Magnesium Compound

[0044] A mixture of MgCl₂ 15 g, AlCl₃ 4.2 g and toluene 550 ml was addedto 1.0 l reaction vessel which is replaced with nitrogen atmosphere andequipped with a mechanical agitator, and the reaction vessel wasagitated at 400 rpm, and then after adding tetrahydrofuran 30 ml,butanol 28 ml, ethanol 1.4 ml, silicon tetraethoxide 1.5 ml andtributylphosphate 3.0 ml to the reaction vessel and the temperature wasraised to 105° C., and then the reaction was conducted at thistemperature for 4 hours. The uniform solution obtained after thecompletion of reaction was cooled to room temperature.

[0045] Step 2: Preparation of Solid Support Materials

[0046] The magnesium solution prepared in the step 1 was transferred toa 1.6 l reaction vessel whose temperature was maintained at 13° C. Theagitation speed was controlled at 350 rpm, and then TiCl₄ 15.5 ml wasadded and the reaction temperature was raised to 90° C. During thisprocesses, solid support materials are precipitated. The reaction wascontinued for 1 hour at 90° C. and then the agitation was stopped,thereby precipitated the solid support materials produced. After thecompletion of precipitation process, the solid support materialseparated from supernatants was washed with 75 ml of toluene twice.

[0047] Step 3: Preparation of the Solid Titanium Catalyst

[0048] After adding toluene 100 ml and TiCl₄ 100 ml to the solid supportmaterial, the temperature of the reaction vessel was raised to 110° C.and maintained for 1 hour at this temperature. Agitation was stopped,the solid support material was precipitated and then supernatant wasseparated, and toluene 100 ml and TiCl₄ 100 ml was added and thendiisophthalate 2.9 ml was added. The temperature of the reaction vesselwas raised again to 120° C. and the reaction vessel was agitated for 1hour. Agitation was stopped, the supernatant was separated, and thenadding toluene 100 ml, reaction vessel temperature was cooled to 70° C.and the reaction vessel was agitated for 30 minutes. Agitation of thereaction vessel was stopped and the supernatant was separated, and thenthe solid titanium catalyst was prepared by adding TiCl₄ 100 ml andagitating for 30 minutes at 70° C.

[0049] Step 4: Surface Treatment of the Solid Titanium Catalyst

[0050] The solid titanium catalyst thus prepared was washed 5 times withpurified hexane 75 ml, and then hexane 500 ml and divinyldimethyl silane50 ml was added and the reaction was carried out for 1 hour at roomtemperature. The catalyst thus prepared was dried under the nitrogenatmosphere and then stored. The surface treated solid titanium catalystwas contained 2.5 weight percent of titanium atom.

[0051] Step 5: Prepolymerization

[0052] A 0.5 l reaction vessel for high pressure reaction was washedwith propylene, and then 2 g of catalyst obtained in the above step 4,hexane 300 ml, triethylaluminum 6 mmol,polydimethylsiloxane(H₂C═CH—Si(CH₃)₂—O—Si(CH₃)₂—CH═CH₂ ) with doublebond at the terminal group 20 ml was added to this reaction vessel, thepressure was controlled to 0.9 atm with ethylene, and then thepolymerization reaction was conducted for 5 hours at 20° C. For theprepolymerized catalyst thus obtained, the amount of macromonomerspolymerized around the catalyst was 31.0 g per 1 g catalyst.

[0053] Step 6: Polymerization

[0054] A 2 l reaction vessel for high pressure reaction was washed withpropylene, and then 20 mg of prepolymerized catalyst thus prepared andcontained within a glass bottle was setted within this reaction vessel,and after the inside of the reaction vessel was made into nitrogenstate/vacuum state three times alternatively, and then made intoatmospheric pressure state. Triehtylaluminum 7 mmol,dicyclopenyldimethoxy silane 0.5 mmol, diisopropyldimetoxy silane 0.5mmol was added to the reaction vessel. Further, hydrogen 300 Nml wasadded, and subsequently propylene in the liquid state 1,200 ml wasadded, and then the temperature was raised to 65° C. while agitating,the polymerization reaction was conducted for 1 hour at thistemperature. After the completion of the polymerizatio reaction,unreacted gases were exhausted, after the reaction vessel was cooled toroom temperature, it was dismembered. The polymers thus obtained werecollected and dried in a vacuum oven for more than 6 hours at 50° C. Asa result, a white polymer was obtained

[0055] Step 7: Measurement of the Melt Strength

[0056] The melt strength of the polymer prepared according to the abovepolymerization method was measured by measuring the melt strength of thestrand that is coming out of the die of extruder (Blabender) at 220° C.by using Reotense (QötFerster, Germany), and the result was shown in thefollowing Table I. When measuring, the diameter of the die was 2 mm, thedistance from the entrance of the die to Reotense roller was 10 cm.

EXAMPLE 2

[0057] This example is the same as in the example 1 except that(H₂C═CH—Si(CH₃)₂—O—(Si(CH₃)₂—O)₃—Si(CH₃)₂—CH═CH₂) is used as vinylterminated polysiloxane with double bond at the terminal group duringthe prepolymerization reaction of the macromonomers, and the meltstrength of the polymer thus prepared was measured, the result was shownin the following Table I.

EXAMPLE 3

[0058] This example is the same as in the example 1 except that(H₂C═CH—Si(CH₃)₂—O—(Si(CH₃)₂—O)₅—Si(CH₃)₂—CH═CH₂) is used as vinylterminated polysiloxane with double bond at the terminal group duringthe prepolymerization reaction of the macromonomers, and the meltstrength of the polymer thus prepared was measured, the result was shownin the following Table I.

EXAMPLE 4

[0059] This example is the same as in the example 1 except that(H₂C═CH—Si(CH₃)₂—O—(Si(CH₃)₂—O)₂₁—Si(CH₃)₂—CH═CH₂) is used as vinylterminated polysiloxane with double bond at the terminal group duringthe prepolymerization reaction of the macromonomers, and the meltstrength of the polymer thus prepared was measured, the result was shownin the following Table I.

EXAMPLE 5

[0060] This example is the same as in the example 1 except that(H₂C═CH—Si(CH₃)₂—O—(Si(CH₃)₂—O)₃₅—Si(CH₃)₂—CH═Cl₂) is used as vinylterminated polysiloxane with double bond at the terminal group duringthe prepolymerization reaction of the macromonomers, and the meltstrength of the polymer thus prepared was measured, the result was shownin the following Table I.

EXAMPLE 6

[0061] This example is the same as in the example 1 except that(H₂C═CH—Si(CH₃)₂—O—(Si(CH₃)₂—O)₅₂—Si(CH₃)₂—CH═CH₂) is used as vinylterminated polysiloxane with double bond at the terminal group duringthe prepolymerization reaction of the macromonomers, and the meltstrength of the polymer thus prepared was measured, the result was shownin the following Table I.

EXAMPLE 7

[0062] This example is same as in the example 1 except that 1000 Nml ofhydrogen was added during the prepolymerization reaction of themacromonomers, and the result was shown in the following Table I.

EXAMPLE 8

[0063] This example is same as in the example 1 except that 50 Nml ofhydrogen was added during the prepolymerization reaction of themacromonomers, and the result was shown in the following Table I.

EXAMPLES 9

[0064] This example is same as in the example 1 except that propylenemonomer was used instead of ethylene monomer during theprepolymerization reaction of the macromonomers, and the result wasshown in the following Table

Comparative Example 1

[0065] This example is same as in the example 1 except that theprepolymerization reaction of the macromonomers was not conducted, andthe melt strength of the polymer thus prepared was measured, the resultwas shown in the following Table I. TABLE 1 Polymerization activity(kg-PP/g-cat) MI (g-PP/10 min) Melt strength (mN) Example 1 32 0.8 172Example 2 32 0.9 143 Example 3 30 1.1 121 Example 4 29 1.4 97 Example 528 1.4 84 Example 6 28 1.4 75 Example 7 34 1.9 142 Example 8 26 0.2 212Comparative 36 1.5 40 example 1

[0066] As shown in above examples and comparative examples, according tothe polymerizaton method of the present invention using prepolymerizedcatalyst, the melt strength of the polymer can be increased withoutcausing big changes in the polymerization activity in comparison withthe polymerization method using conventional catalyst.

[0067] As a result, by using the present catalyst for olefinpolymerization and the method for the same, the polyolefin with meltstrength suitable for the use of process which is carried out in themelt state such as foaming, heat shaping and extrusion coating can beeffectively provided.

What is claimed is:
 1. A prepolymerized olefin polymerization catalystencapsulated with macromolecular monomers around said catalyst, saidprepolymerized catalyst being prepared by prepolymerization of olefinmonomer and vinyl terminated polysiloxane compound with double bond atthe terminal group in the presence of solid titanium catalyst for olefinpolymerization, said solid titanium catalyst being prepared by surfacetreating solid titanium catalyst composed of magnesium compound,titanium compound and electron donor with silane compound having two ormore of vinyl groups.
 2. The prepolymerized olefin polymerizationcatalyst of claim 1, wherein said silane compound having two or more ofvinyl groups is divinyldimethylsilane, divinyldiphenylsilane,divinyldiethylsilane, divinyldiisobutylsilane or divinyldihydridesilane.3. The prepolymerized olefin polymerization catalyst of claim 1, whereinthe amount of said silane compound having two or more of vinyl groupsused is 2˜200 mole per 1 mole of magnesium compound.
 4. Theprepolymerized olefin polymerization catalyst of claim 1, wherein saidsolid titanium catalyst is prepared by the steps of (i) preparingsolution of magnesium compound by dissolving magnesium compound havingno reducibility into electron donors, (ii) reacting said magnesiumsolution with transition metal compounds, silicone compounds, tincompounds or a mixture thereof and thereby precipitating solidparticles, and (iii) reacting said precipitated solid particles withtitanium compounds and electron donors.
 5. The prepolymerized olefinpolymerization catalyst of claim 1, wherein said olefin monomer used inthe prepolymerization step is one or more monomer selected from thegroup consisting of ethylene, propylene, 1-butene, 1-hexene and1-octene.
 6. The prepolymerized olefin polymerization catalyst of claim1, wherein said vinyl terminated polysiloxane compound with double bondat the terminal group is of the following structure:H₂C═CH—SiR₂—O—(SiR₂—O)_(n)—SiR₂—CH═CH₂ (n=0˜100, R=alkyl, alkoxy,hydrogen or phenyl).
 7. The prepolymerized olefin polymerizationcatalyst of claim 1, wherein said macromolecular monomers encapsulatingsaid prepolymerized catalyst has weight average molecular weight in therange of 500˜100,000, and is composed of 1˜99 weight percent of olefin,0.01˜10 weight percent of vinyl terminated polysiloxane compound withdouble bond at the terminal group, and 0.001˜1 weight percent of silanematerial.
 8. A method for polymerization of olefin by using the catalystsystem comprising: (a) the prepolymerized olefin polymerization catalystof one of claims 1 through 7, (b) organometallic compound of Group I orIII metals of the Periodic Table, (c) external electron donor.
 9. Themethod for polymerization of olefin of claim 8 wherein saidorganometallic compound is trialkylaluminum.
 10. The method forpolymerization of olefin of claim 8 wherein said external electron donoris alkoxy silane compound.